Molecule-based assemblies of transition metals bridged by organonitrile or cyanide ligands are proposed. Key objectives are to synthesize, crystallize and measure the magnetic and conducting properties of chain, layered, and 3-D compounds. Central to these studies is the use of acetonitrile metal complexes and coordinatively unsaturated metal complexes that undergo facile substitution or adduct reactions with ligands containing isocyanate or cyanate functionalities. Molecular precursors for these studies include a number of known compounds as well as new metal and organic molecules that are designed to tailor the dimensionality of the structures and to mediate properties. The molecular precursors will be characterized by NMR or EPR spectroscopy, mass spectrometry and x-ray crystallography. New paramagnetic cyanide and acetonitrile complexes of 3d metals will be designed for use in reactions to form macromolecular arrays of ferro- or ferrimagnetically coupled chains or 2-D networks. Structures with two cyanide ligands in either cis or trans orientations are used to influence the dimensionality of extended arrays prepared from them. In addition to architectures based on octahedral and tetrahedral building blocks, frameworks based on novel cubic octacyanide dimetallate building blocks prepared in our laboratories are also proposed. Issues to be addressed in this work are solubility problems, steric arrangements that diminish ?-stacking or organic radicals, and the crystallization of soluble oligomers whose properties and structures aid in the characterization of corresponding polymers. In lieu of x-ray data for the oligomers, it will be important to obtain structural information from MALDI and/or electrospray mass spectrometry.